1. Field of the Invention
The present invention relates to a gas-liquid separation method and unit, and particularly relates to a gas-liquid separation method and unit suitable for removing a byproduct gas generated in a reaction for forming metal microparticles with a continuous production process of the metal microparticles.
2. Description of the Related Art
Magnetic particles contained in a magnetic layer constituting a magnetic recording medium have preferably small particle sizes and superior monodispersibility from the viewpoint of the quality. In producing the metal microparticles, a reaction for forming the metal microparticles is occasionally accompanied by the generation of a byproduct gas (for instance, hydrogen gas).
The reaction accompanied by the byproduct gas is so hardly continued that a continuous processing apparatus for continuously producing the above described metal microparticles has not yet practically been realized. That is because 1 mol of a byproduct gas produces the byproduct gas expanded to as large a volume as 22.4 l, and in the case of continuous treatment, unless the byproduct gas can be effectively removed in the flow of the continuous treatment, it causes various detrimental effects. For instance, if the byproduct gas can not be effectively removed in the flow of the continuous treatment, the flow of the continuous treatment becomes unstable to make a mixing field and a reaction field nonuniform, and thereby to make the equilibrium of the reaction hardly proceed to a reaction-accelerating direction. In addition, when a temperature of a solution is controlled for the reaction, if the byproduct gas can not be effectively removed in the flow of the continuous treatment, the reaction temperature can not be accurately controlled, because gas has a low coefficient of thermal conductivity. As a result of the detrimental effects, there arise such problems that the produced metal microparticles increase in particle sizes, and that the monodispersibility gets worse.
There are various general methods for separating and removing gas from liquid. The typical ones include a degassing method with a separating film (for instance, Japanese Patent Application Publication No. 11-333236, Japanese Patent Application Publication No. 7-253272 and Japanese Patent Application Publication No. 2002-52325); a degassing method by using an adsorbent having gas absorptiveness (for instance, Japanese Patent Application Publication No. 2001-113115); a degassing method by decompression; a degassing method by heating; and a degassing method by mechanical methods such as a cyclone method and a trapping method (for instance, Japanese Publication of International Patent Application No. 2002-529228, Japanese Publication of International Patent Application No. 2002-529233 and Japanese Patent Application Publication No. 11-281637).